Definitions:

1. a male person who is a fellow member of a fraternity or religion or other group noun
   • None of their brothers would betray them.
2. a male with the same parents as someone else noun
   • my brother still lives with our parents

Synonyms:

• blood brother
• chum
• comrade

NearBy Words:

• brother-in-law
• brotherhood
• brotherlike
• brotherly